Modeling the longitudinal transitions of electronic cigarettes and conventional cigarettes with time-dependent covariates among adolescents.

Introduction:
This text provides an analysis of the relationship between electronic cigarette (e-cigarette) use and cigarette use among adolescents. The study aims to investigate the transitions between e-cigarette use and cigarette use over time while considering time-dependent covariates. The findings offer valuable insights for policymakers and regulators regarding the potential impact of e-cigarette use on youth smoking behaviors.

Key Points:

* The study uses data from the happiness and health Study, a prospective cohort study of high school students from 10 schools in Southern California.
* Four states are created to describe the use of two products (e-cigarettes and cigarettes) in the past 6 months: use of neither product, cigarette use only, e-cigarette use only, and use of both cigarettes and e-cigarettes.
* The analysis focuses on modeling the transition probabilities from one state to another state, resulting in a total of sixteen possibilities.
* Seven self-reported risk factors are considered as covariates: family history of cigarettes, age, gender, ethnicity, delinquency tendencies, friends' use of cigarettes, and susceptibility to cigarette use.
* Crude odds ratios, single outcome logistic regression models, and joint polytomous logistic regression models are used to analyze the data and estimate transition probabilities.
* The results indicate that use of one product is associated with increased odds of using the other product among non-users, and decreased odds of abstention from use among users of both products.
* The study found that prevention efforts focused on both e-cigarettes and cigarettes are needed, as use of either product seems to encourage use of the other.

Main Message:
The study emphasizes the importance of considering the relationship between e-cigarette use and cigarette use among adolescents when developing regulatory policies. The findings suggest that e-cigarette use is associated with increased odds of cigarette use initiation and reduced odds of cigarette abstention. as a result, regulatory measures should address both e-cigarette and cigarette use to effectively reduce smoking behaviors among youth.

Yang Z, Berhane K, Leventhal aM, Liu M, Barrington-Trimis JL, Thomas DC. Modeling the longitudinal transitions of electronic cigarettes and conventional cigarettes with time-dependent covariates among adolescents. Preventive medicine. 2022;164:107294. doi:10.1016/j.ypmed.2022.107294